I am trying to make the point that not even the most respectful, careful, restrained and considered approach has made one scrap of difference to the man in question. It's all been tried. So you have a choice. Let him keep on with it (and he will, as all evangelical types do), or slap him down. As far as I'm concerned, if he disrespects scientists without grounds or evidence he deserves every bit of flak chucked at him.